"We found use of uptalk in all of our speakers, despite their diverse backgrounds in socioeconomic status, ethnicity, bilingualism and gender," said Amanda Ritchart, a linguist at the University of California who led the research.

"We believe that uptalk is becoming more prevalent and systematic in its use for the younger generations in Southern California," she added.

The team recorded and analysed the voices of 23 native Californians aged between 18 and 22. The researchers were therefore not able to infer similar language patters in older Californians.